Longitudinal impacts of childhood neighborhood air pollution exposure on white matter integrity and cognition during childhood to early adolescence.

Particulate matter (PM2.5) has been linked with brain and cognitive changes; however, longitudinal evidence characterizing associations with white matter (WM) development across adolescence remains limited. This study examined longitudinal associations between baseline PM2.5 and fronto-limbic WM integrity), as well as separately examined associations with cognition and substance use (SU), across adolescence. Baseline Adolscent Brain Cognitive Development (ABCD) Study (n = 4,511; 47.4% female; mean age = 9.9 years, SD = 0.5, range = 9-11; 57.0% White, 10.5% Black, 20.4% Hispanic, 2.3% Asian, and 9.8% multiracial). Linear mixed effects/logistical regression tested for PM2.5 interactions with age/sex, controlling for neighborhood factors. PM2.5 and fronto-limbic mean diffusivity (MD) and fractional anisotropy (FA) associations were observed, Cohen's d effect sizes were reported. At age 9, increased PM2.5 was associated with increased FA in the anterior thalamic radiation (ATR), fornix, and uncinate fasciculus (UNC), whereas by age 14, PM2.5 was linked with reduced FA in all tracts. In the superior longitudinal fasciculus (SLF), PM2.5 was linked to increased MD at age 9 and reduced FA at ages 12 and 14. We also observed reductions in MD in the fornix at ages 12 and 14, and in the SLF and UNC at age 14. The links between PM2.5 and cognition and SU were not significant. Findings suggest the association between baseline PM2.5 exposure and fronto-limbic WM varies as a function of age at assessment, with positive associations observed at younger ages and negative associations at older ages.